2020 has tied with 2016 as the hottest year on record, marking the end of the hottest decade in the books as the world grapples with global climate change, according to a study released Friday.
The finding by the Copernicus Climate Change Service, an intergovernmental agency that supports European climate policy, continues a relentless upward trend in global temperatures due to greenhouse gas emissions trapping heat in the atmosphere.
"2020 stands out for its exceptional warmth in the Arctic and a record number of tropical storms in the North Atlantic," said Carlo Buontempo, director of Copernicus service.
"It is no surprise that the last decade was the warmest on record, and is yet another reminder of the urgency of ambitious emissions reductions to prevent adverse climate impacts in the future," he said.
The evidence of record heat in 2020 mounted throughout the year: Dry and hot conditions fueled massive record-breaking wildfires in Australia and later in the U.S. West; Arctic sea ice plummeted to its second-lowest levels on record; and worldwide, monthly temperature records were shattered.
Last year was 0.6 degree Celsius (1.08 degrees Fahrenheit) above the average for the period between 1981 and 2010 and about 1.25 degrees Celsius (2.25 degrees Fahrenheit) above the average for the preindustrial period between 1850 and 1900, according to the agency.
Some parts of the world heated up more than others as carbon emissions continued to rise. Europe had its hottest year on record, with temperatures that were 1.4 degree Celsius (2.53 degrees Fahrenheit) hotter than 2019, which was previously the warmest year.
The Arctic and northern Siberia saw the largest temperature surges, reaching over 6 degrees Celsius (10.8 degrees Fahrenheit) above average for the year. Western Siberia had an exceptionally hot winter and spring, while the Siberian Arctic and much of the Arctic Ocean had exceptionally hot temperatures in summer and autumn.
Major wildfires near the Arctic Circle also released a record amount of carbon emissions in 2020 and Arctic sea ice hit record lows for the months of July and October.
"Until the net global emissions reduce to zero, CO2 will continue to accumulate in the atmosphere and drive further climate change," said Vincent-Henri Peuch, director of the Copernicus Atmosphere Monitoring Service.
2016, the previous hottest year, was very hot because temperatures had been impacted by an El Nino, which sent a significant amount of heat from the Pacific Ocean into the atmosphere. The last six years were the warmest six on record.
— Graphics by CNBC's Nate Rattner